Method for depositing metallic nitride series thin film

ABSTRACT

The present invention generally relates to a method for depositing a metallic nitride series thin film, typically a TiN-series thin film. The TiN-series thin film according to the present invention is formed by a CVD, and contains Ti, O and N to have a higher barrier characteristic than those of conventional TiN thin films, so that TiN-series thin film can suitably used as a barrier layer. In addition, a TiN-series thin film according to the present invention is formed by a CVD, and contains Ti, N and P to have a lower resistance than those of conventional TiN films, so that TiN-series thin film can suitably used as a barrier layer or a capacitor top electrode. Moreover, if a TiN-series thin film containing Ti, O, N and P is formed by a CVD, the TiN-series thin film can have both of a high barrier characteristic and a low resistance characteristic.

CROSS REFERENCE TO RELATED APPLICATION

This is a continuation-in-part application of patent application Ser.No. 09/660,546 filed on Sep. 12, 2000, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a method for depositing ametallic nitride series thin film, typically a TiN-series thin film,which is used as, e.g., a barrier layer, a capacitor top electrode, agate electrode or a contact part, in a semiconductor device.

2. Description of the Related Art

In the production of semiconductor devices, the construction of circuitstends to have a multilayer metallization structure on a recent demandfor higher density and higher density integration. Therefore, anembedding technique for electrical connections between layers, such as acontact hole which is a connecting part between a bottom semiconductordevice layer and a top wiring layer, and a via hole which is aconnecting part between top and bottom wiring layers, is important. Inaddition, with the high-density integration, a technique for depositinga top electrode of capacitor gate material of a DRAM memory part, at ahigh coverage is important. Recently, a high dielectric material, suchas Ta₂O₅, is used as a capacitor gate material.

In the embedding of the contact hole and via hole of the above describedtechniques, Al (aluminum), W (tungsten) or an alloy mainly containing Alor W is generally used. If such a metal or alloy directly contacts anunderlying Si (silicon) substrate or Al wiring, there is the possibilitythat an alloy of both metals is formed due to the Si-suction effect ofAl (counter diffusion) in the boundary portion between the metals. Thealloy thus formed has a large value of resistance, so that the formationof such an alloy is not preferred from the point of view of the decreaseof power consumption and high speed operation which are recentlyrequired for devices.

In addition, when W or a W alloy is used as an embedded layer for acontact hole, WF₆ gas used for forming the embedded layer tends to reactwith silicon of the substrate to deteriorate electrical characteristicsto obtain undesired results.

Therefore, in order to prevent these disadvantages, before an embeddedlayer is formed in a contact hole or a via hole, a barrier layer isformed on the inner walls thereof, and the embedded layer is formedthereon. In this case, as the barrier layer, a double layer structure ofa Ti (titanium) film and a TiN (titanium nitride) film is generallyused.

Conventionally, such a barrier layer is deposited using a physical vapordeposition (PVD). Recently, the scale down and high density integrationof devices are particularly required, and the design rule isparticularly severe. In accordance therewith, the line width and thediameter of holes further decrease and the aspect ratio increases. As aresult, the embedding performance of the PVD film is bad, so that it isnot possible to ensure a sufficient contact resistance.

Therefore, the Ti film and TiN film constituting the barrier layer aredeposited by a chemical vapor deposition (CVD) capable of expecting toform a better quality of film. When the Ti film is deposited by the CVD,TiCl₄ (titanium tetrachloride) and H₂ (hydrogen) are used as reactiongases to be activated as plasma to deposit the film. When the TiN filmis deposited, TiCl₄ and NH₃ (ammonia) or MMH (monomethyl hydrazine) areused as reaction gases.

On the other hand, as described above, with the high densityintegration, a high dielectric material, such as Ta₂O₅, is used as acapacitor gate material in order to obtain a high capacitance withoutchanging scale. However, such a high dielectric material is not morestable than SiO₂ which has been conventionally used as a capacitor gatematerial. Therefore, when a polysilicon, which has been conventionallyused as a top electrode, is used, it is oxidized by heat history afterthe preparation of a capacitor, so that it is impossible to form astable device. Therefore, TiN or the like, which is more difficult to beoxidized, is required as a top electrode.

Also in the case of this technique, the TiN film or the like has beenconventionally deposited by the above described PVD. However, a recenthighly integrated capacitor type, which requires a high coverage, e.g.,a crown type, a fin type, or a RUG polysilicon, which has irreguralitiesformed on a polysilicon layer in order to increase the capacity of acapacitor when the crown type or fin type is formed, can not bedeposited as a top electrode.

Therefore, a TiN film constituting a capacitor top electrode is alsodeposited by a CVD which is expected to be capable of forming a betterquality of film at a high coverage. Also in this case, TiCl₄ and NH₃ orMMH are used as reaction gases for depositing the TiN film.

By the way, when a Tin film is thus deposited by the CVD, Cl (chlorine)remains in the film, so that the deposited film has a high specificresistance. If the specific resistance is so high, it is not possible toobtain sufficient characteristics when it is applied to a capacitor topelectrode. In addition, the formed film is a high stress film. Moreover,the TiN film, which is a columnar crystal, has a low barriercharacteristic since intergranular diffusion is easy to occur therein.In particular, the low barrier characteristic causes problems when theTiN film is used as a barrier layer for a Cu (copper) wiring or when theTiN film is used as an oxygen diffusion barrier, on the occasion offorming a Ta₂O₅ capacitor top electrode. That is, the corrosion of theCu wiring due to the remaining chlorine and the decrease of the capacityof Ta₂O₅ due to the diffusion of O (oxygen), which increases thethickness of the Ta₂O₅ film, cause problems.

SUMMARY OF THE INVENTION

The inventor has found that a TiN-series thin film, which is depositedby a CVD and which contains Ti, O and N (nitride), has a higher barriercharacteristic than that of a conventional TiN film, and is suitable fora barrier layer. In addition, the inventor has found that a TiN-seriesthin film, which is deposited by a CVD and which contains Ti, N and P(phosphorus), has a lower resistance than that of a conventional TiNfilm, and is suitable for a barrier layer and a capacitor top electrode.Moreover, the inventor has found that the TiN-series thin filmsimultaneously containing O and P having the above described functionshas both of a high barrier characteristic and a low resistancecharacteristic.

It is therefore an object of the present invention to provide a methodfor depositing a high-quality metallic nitride series, typicallyTiN-series, thin film having a higher barrier characteristic and/or alower resistance than those of a conventional TiN film formed by a CVD.

The present invention also relates to a method for producing a filmstructure including such a metallic nitride series thin film.

Therefore, there is provided a method for depositing a TiN-series thinfilm, said method comprising the steps of: arranging a substrate in aprocess vessel; evacuating said process vessel, while heating saidsubstrate; pre-heating said substrate while introducing a N₂ gas and aNH₃ gas into said process vessel; pre-flowing a TiCl gas and anO-containing gas, without introducing same into said process vessel; andintroducing said TiCl₄ gas, said N₂ gas, said NH₃ gas and saidO-containing gas into said process vessel to form a thin film containingTi, O and N on said substrate by a CVD, wherein flow rates of said gasesin said pre-flowing step are equal to those in said introducing step.

There is also provided a method for depositing a TiN-series thin film,said method comprising the steps of: arranging a substrate in a processvessel; evacuating said process vessel, while heating said substrate;pre-heating said substrate while introducing a N₂ gas and a NH₃ gas intosaid process vessel; pre-flowing a TiCl₄ gas, an O-containing gas and aPH₃ gas, without introducing same into said process vessel; andintroducing said TiCl₄ gas, said N₂ gas, said NH₃ gas, said O-containinggas and said PH₃ gas into said process vessel to form a thin filmcontaining Ti, O, N and P on said substrate by a CVD.

There is also provided a method for depositing a TiN-series thin film,said method comprising the steps of: arranging a substrate in a processvessel; evacuating said process vessel, while heating said substrate;pre-heating said substrate while introducing a N₂ gas and a NH₃ gas intosaid process vessel; pre-flowing a TiCl₄ gas and an O-containing gas,without introducing same into said process vessel; introducing saidTiCl₄ gas, said N₂ gas, said NH₃ gas and said O-containing gas into aprocess vessel to form a first thin film containing Ti, O and N by aCVD; pre-flowing TiCl₄ gas and PH₃ gas, without introducing same intosaid process vessel; and introducing said TiCl₄ gas, said N₂ gas, saidNH₃ gas and said PH₃ gas into said process vessel to form a second thinfilm containing Ti, N and P on said first thin film by a CVD.

There is also provided a method for depositing a TiN-series thin film,said method comprising the steps of: arranging a substrate in a processvessel; evacuating said process vessel, while heating said substrate;pre-heating said substrate while introducing a N₂ gas and a NH₃ gas intosaid process vessel; pre-flowing a TiCl₄ gas and a first O-containinggas, without introducing same into said process vessel; introducing saidTiCl₄ gas, said N₂ gas, said NH₃ gas and said first O-containing gasinto a process vessel to form a first thin film containing Ti, O and Nby a CVD; pre-flowing a TiCl₄ gas and a PH₃ gas, without introducingsame into said process vessel; introducing said TiCl₄ gas, said N₂ gas,said NH₃ gas and said PH₃ gas into said process vessel to form a secondthin film containing Ti, N and P on said first thin film by a CVD;pre-flowing a TiCl₄ gas and a second O-containing gas, withoutintroducing same into said process vessel; and introducing said TiCl₄gas, said N₂ gas, said NH₃ gas and said second O-containing gas intosaid process vessel to form a third thin film containing Ti, O and N onsaid second thin film by a CVD.

There is also provided a method for depositing a TiN-series thin film,said method comprising the steps of: arranging a substrate in a processvessel; evacuating said process vessel, while heating said substrate;pre-heating said substrate while introducing a N₂ gas and a NH₃ gas intosaid process vessel; pre-flowing a TiCl₄ gas and a PH₃ gas, withoutintroducing same into said process vessel; and introducing said TiCl₄gas, said N₂ gas, said NH₃ gas and said PH₃ gas into said process vesselto form a thin film containing Ti, N and P on said substrate by a CVD.

There is also provided a method for producing a film structure, saidmethod comprising the steps of: forming a first conductive layer on asubstrate; forming a TiN-series thin film on said first conductivelayer; and forming a second conductive layer on said TiN-series thinfilm, wherein said step of forming a TiN-series thin film includes thesub-steps of: arranging said substrate in a process vessel; evacuatingsaid process vessel, while heating said substrate pre-heating saidsubstrate while introducing a N₂ gas and a NH₃ gas into said processvessel; pre-flowing a TiCl₄ gas and at least one of an O-containing gasand a PH₃ gas, without introducing same into said process vessel; andintroducing said TiCl₄ gas, said N₂ gas, said NH₃ gas, and said at leastone of said O-containing gas and said PH₃ gas into said process vesselto form a thin film containing Ti, N, and at least one of O and P onsaid first conductive layer by a CVD, wherein flow rates of said gasesin said pre-flowing step are equal to those in said introducing step.

As described above, the TiN-series thin film formed by the methodaccording to the present-invention contains Ti, O and N to have a higherbarrier characteristic than those of conventional TiN films, so that theTiN-series thin film is suitable for a barrier layer. In addition, theTiN-series thin film according to the present invention is formed by aCVD and contains Ti, N and P to have a lower resistance than those ofconventional TiN films, so that the TiN-series thin film is suitable fora barrier layer or a capacitor top electrode.

In addition, the TiN-series thin film, which is formed by a CVD andwhich contains Ti, O, N and P, can have both of a high barriercharacteristic and a low resistance characteristic.

Moreover, if the TiN-series thin film has a stacked structure of a firstthin film which is formed by a CVD and which contains Ti, O and N, and asecond thin film which is formed by a CVD and which contains Ti, N andP, the high barrier characteristic of the first layer and the lowresistance characteristic of the second layer can provide obtaincharacteristics which are the same as or superior to conventionalbarrier layers even if the thickness is smaller than the conventionalbarrier layers.

In addition, if the TiN-series thin film has a stacked structure of afirst thin film which is formed by a CVD and which contains Ti, O and N,a second thin film which is formed by a CVD and which contains Ti, N andP, and a third thin film which is formed by a CVD and which contains Ti,O and N, it is possible to obtain the barrier characteristic againstlayers on both sides.

Moreover, in a semiconductor device, these TiN-series thin films areused as (1) a barrier layer or an embedded wiring portion in a contactpart between a wiring layer and a semiconductor substrate or aconductive layer arranged thereon, (2) a top electrode layer, barrierlayer or bottom electrode of a capacitor portion having an insulatinglayer of Ta₂O₅, RuO and so forth, (3) at least a part of a gateelectrode, and (4) a contact structure on a major surface of asemiconductor substrate, so that it is possible to obtain excellentcharacteristics.

According to the present invention, it is possible to deposit suchTiN-series thin films of high-quality by carrying out the pre-heatingstep and/or the pre-flowing step. Specifically, by carrying out thepre-heating step, it is possible to stabilize the temperature of thesubstrate before the later step of forming a thin film. By carrying outthe pre-flowing step, it is possible to stabilize the flows of the TiCl₄gas, the O-containing gas and/or the PH₃ gas before the next step ofintroducing those gases into the process vessel, i.e. the step offorming a thin film. In addition, by carrying out the pre-flowing step,it is possible to precisely control the flow rates of those gases in thenext step of forming a thin film, even if the flow rates are very small.It is more effective to equalize the flow rates in the pre-flowing stepwith those in the next step of forming a thin film.

According to the present invention, there is also provided a method fordepositing a metallic nitride series thin film, said method comprisingthe steps of: arranging a substrate in a process vessel; evacuating saidprocess vessel, while heating said substrate; pre-heating said substratewhile introducing an inert gas and a reducing gas into said processvessel; pre-flowing a metallic-element containing gas and at least oneof an O-containing gas, a PH₃ gas and a B₂H₆ gas, without introducingsame into said process vessel; and introducing said metallic-elementcontaining gas, said inert gas, said reducing gas, and at least one ofsaid O-containing gas, a PH₃ gas and a B₂H₆ gas into said process vesselto form a metallic nitride thin film containing at least one of O, P andB on said substrate by a CVD, wherein flow rates of said gases in saidpre-flowing step are equal to those in said introducing step.

There is also provided a method for producing a film structure, saidmethod comprising the steps of: forming a dielectric layer on a firstconductive layer; forming a metallic nitride series thin film on saiddielectric layer; and forming a second conductive layer on said metallicnitride series thin film, wherein said step of forming a metallicnitride series thin film includes the sub-steps of: pre-flowing ametallic-element containing gas without introducing same into a processvessel; and introducing said metallic-element containing gas, a N₂ gas,a NH₃ gas, and at least one of an O-containing gas, a PH₃ gas and a B₂H₆gas into a process vessel to form said metallic nitride series thin filmcomprising at least one of a thin film containing said metallic-element,O and N, a thin film containing said metallic-element, N and P, a thinfilm containing said metallic-element, N and B, a thin film containingsaid metallic-element, O, N and P and a thin film containing saidmetallic-element, O, N and B, by a CVD.

There is also provided a method for depositing a metallic nitride seriesthin film, said method comprising the steps of: arranging a substrate ina process vessel; evacuating said process vessel, while heating saidsubstrate; pre-heating said substrate while introducing a N-containinggas into said process vessel; pre-flowing a metallic-element containinggas without introducing said metallic-element containing gas into saidprocess vessel; and introducing said metallic-element containing gas, aninert gas and a reducing gas into said process vessel to form a metallicnitride series thin film on said substrate by a CVD, wherein flow rateof said metallic-element containing gas in said pre-flowing step isequal to that in said introducing step.

Thus, according to the present invention, it is possible to deposit suchmetallic nitride series thin films of high-quality by carrying out thepre-heating step and/or the pre-flowing step.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be understood more fully from the detaileddescription given here below and from the accompanying drawings of thepreferred embodiments of the invention. However, the drawings are notintended to imply limitation of the invention to a specific embodiment,but are for explanation and understanding only.

In the drawings:

FIG. 1 is a sectional view of a deposition system for depositing aTiN-series thin film according to the present invention;

FIG. 2 is a graph showing the relationship between flow ratios O₂/NH₃and the specific resistance values of a TiON thin film;

FIG. 3 is a graph showing the relationship between flow ratios PH₃ andthe specific resistance values of a TiN-series thin film;

FIG. 4 is a graph showing the relationships between depositiontemperatures and the specific resistance values of a TiN-series thinfilm when PH₃ is used and is not used;

FIG. 5 is a graph showing the relationships between flow ratios O₂/NH₃and the specific resistance values of a TiN-series thin film when PH₃ isuse and is not used;

FIG. 6 is a sectional view showing examples (a) and (b) of a stackedstructure of a TiN-series thin film according to the present invention;

FIG. 7 is a sectional view of a film structure using a TiN-series thinfilm according to the present invention;

FIG. 8 is a sectional view showing examples (a) through (c) of aTiN-series thin film according to the present invention which is usedfor a contact part of a metal wiring layer;

FIG. 9 is a sectional view showing examples (a) through (c) of aTiN-series thin film according to the present invention which is usedfor a capacitor structure of a DRAM or the like;

FIG. 10 is a schematic view showing an example of a deposition systemcapable of continuously depositing a TiN-series thin film and otherfilms according to the present invention;

FIG. 11 is a sectional view showing examples (a) and (b) of a TiN-seriesthin film according to the present invention which is used for a gateelectrode;

FIG. 12 is a sectional view showing examples (a) and (b) of a TiN-seriesthin film according to the present invention which is used for a gateelectrode; and

FIG. 13 is a sectional view showing an example of a TiN-series thin filmaccording to the present invention which is used for a contact structurewhen a wiring is formed in a diffusion region formed in a major surfaceof a semiconductor substrate.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the accompanying drawings, the preferred embodiments ofthe present invention will be described in detail below.

FIG. 1 is a sectional view of a deposition system for depositing aTiN-series thin film according to the present invention. This depositionsystem has a substantially cylindrical airtight process vessel 11, inwhich a susceptor 12 for horizontally supporting a semiconductor wafer Wserving as an object to be processed is arranged while being supportedon a cylindrical supporting member 13. On the outer edge portion of thesusceptor 12, a guide ring 14 for guiding the semiconductor wafer W isprovided. In addition, a heater 15 is embedded in the susceptor 12. Whenan electrical power is fed to the heater 15 from a power supply 16, theheater 15 heats the semiconductor waver W, which is an object to beprocessed, to a predetermined temperature. The power supply 16 isconnected to a controller 17 which controls the output of the heater 15in accordance with a signal from a temperature sensor (not shown).

The ceiling wall 11 a of the process vessel 11 is provided with a showerhead 20. In the shower head 20, a large number of gas discharging holes20 a and 20 b for discharging a gas toward the susceptor 12 arealternately formed. To the shower head 20, the piping of a gas supplymechanism 30 is connected. As will be described later, main flow lines45 for supplying TiCl₄ are connected to the gas discharging holes 20 a,and main flow lines 46 for supplying NH₃ gas are connected to the gasdischarging holes 20 b, so that predetermined gases are introduced intothe process vessel 11 via the shower head 20. Thus, the shower head 20is a matrix type shower head, and adopts a post mix system wherein TiCl₄and NH₃ gases serving as reaction gases are mixed after being dischargedfrom the discharging holes 20 a and 20 b which are alternately formed.

The gas supply mechanism 30 has a ClF₃ supply source 31 for supplyingClF₃ which is a cleaning gas, an N₂ supply source 32 for supplying N₂, aTiCl₄ supply source 33 for supplying TiCl₄ which is a reaction gas, aPH₃ supply source 34 for supplying PH₃ serving as a P containing gas, anNH₃ supply source 35 for supplying NH₃ which is a reaction gas and whichcontains N and H, and an O₂ gas supply source 36 for supplying O₂serving as an O-containing gas. In addition, a gas line 39 is connectedto the ClF₃ supply source 31, a gas line 40 is connected to the N₂supply source 32, a gas line 41 is connected to the TiCl₄ supply source33, a gas line 42 is connected to the PH₃ supply source 34, a gas line43 is connected to the NH₃ supply source 35, and a gas line 44 isconnected to the O₂ gas supply source 36. Each of the lines 39 through44 is provided with a mass flow controller 48 and first and secondvalves 47, 38 at the upstream side and the downstream side with respectto the mass flow controller 48, respectively.

The gas line 40 extending from the N₂ supply source 32 meets the gasline 41 extending from the TiCl₄ supply source 33, so that TiCl₄ gascarried on N₂ gas flowing through the gas line 40 and the pipe 45 isintroduced into the process vessel 11 via the gas discharging holes 20 aof the shower head 20. The gas line 39 extending from the ClF₃ supplysource 31 meets the gas line 40, so that ClF₃ serving as a cleaning gasis introduced into the process vessel 11 from the gas discharging holes20 a via the gas lines 39 and 40 and the main flow lines 45 by openingthe valve provided in the gas line 39. The gas lines 42, 43 and 44extending from the PH₃, NH₃ and O₂ supply sources 34, 35 and 36 areconnected to the main flow lines 46, so that those gases are introducedinto the process vessel 11 from the gas discharging holes 20 b of theshower head 20.

In addition, this deposition system has pre-flow lines 22, 23 forpre-flowing the gases from the gas supply sources 33, 34 and/or 36, andexhausting those gases before the main flow lines 45 and 46, i.e. beforethe process vessel 11. The pre-flow lines 22, 23 are connected, viathird valves 37, to the corresponding gas lines 41, 42 and 44 betweenthe mass flow controllers 48 and the second valves 38.

As the N-containing gas and the H containing gas, monomethyl hydrazine(MMH) may be used in place of NH₃, or an N-containing gas and an Hcontaining gas may be introduced as separate gases. In addition, as theO-containing gas, NO gas or N₂O gas may be used in place of O₂ gas.Moreover, Ar may be substituted for N₂.

To the bottom wall 11 b of the process vessel 11, an exhaust pipe 18 isconnected. To this exhaust pipe 18, an exhaust system 19 including avacuum pump is connected via an exhaust line 21. By operating theexhaust system 19, the pressure in the process vessel 11 can reduced toa predetermined degree of vacuum. The downstream ends of the pre-flowlines 22, 23 are connected to the exhaust line 21 so that the pre-flowngases are exhausted by the exhaust system 19.

A method for depositing a TiN-series thin film on a semiconductor waferW using such a system will be described below.

First, the semiconductor wafer W is mounted on the susceptor 12 in theprocess vessel 11. Then, while the wafer W is heated by the heater 15,the process vessel 11 is evacuated to a high vacuum state by the exhaustsystem 19. Subsequently, N₂ gas and NH₃ gas are introduced into theprocess vessel 11 at a predetermined flow ratio so that the pressure inthe process vessel 11 is 133 to 1333 Pa, while pre-heating thesemiconductor wafer W at a temperature of about 400 to 700° C.

Then, the pressure in the process vessel 11 is changed to 13.3 to 133Pa, and while the flow rates of N₂ gas and NH₃ gas are maintained, TiCl₄gas and at least one of O₂ gas and PH₃ gas are pre-flown thorough thepre-flow lines 22, 23, without introducing those gases into the processvessel 11, at predetermined flow rates for about 5 to 20 seconds.Subsequently, the deposition of a predetermined TiN-series thin film iscarried out by introducing TiCl₄ gas and at least one of O₂ gas and PH₃gas thorough the main flow lines 45, 46 on the same conditions (flowrates of the gases, pressure in the process vessel 11, and so forth) asthose in the pre-flowing step. At this time, the deposition of theTiN-series thin film is carried out at substantially the sametemperature as that in the pre-heating step.

By carrying out the pre-heating step, it is possible to stabilize thetemperature of the semiconductor wafer W before the later step offorming a thin film. By carrying out the pre-flowing step, it ispossible to stabilize the flows of the TiCl₄ gas, the O-containing gasand/or the PH₃ gas before the next step of introducing those gases intothe process vessel, i.e. the step of forming a thin film. In addition,by carrying out the pre-flowing step, it is possible to preciselycontrol the flow rates of those gases in the next step of forming a thinfilm, even if the flow rates are very small. It is more effective toequalize the flow rates in the pre-flowing step with those in the nextstep of forming a thin film.

After the deposition, the semiconductor wafer is carried out from theprocess vessel 11. Then, ClF₃ gas serving as a cleaning gas isintroduced into the process vessel 11 to clean the interior of theprocess vessel 11.

When NH₃ gas, TiCl gas and O₂ gas are used as process gasses in theabove described deposition, a TiN-series film (TiON film), whichcontains Ti, N and O and which has a high barrier characteristic whilemaintaining a relatively low resistance value, is formed. That is, sincethe crystal of the TiN film is a columnar crystal, the intergranulardiffusion, whereby metal or O may diffuse via the grain boundary of TiNcrystal, is easy to occur therein. Therefor, if the TiN film is formedby the thermal CVD with the O-containing gas, the barrier characteristicof the grain boundary of TiN crystal can be improved. In this case, thevolume ratio of O₂ to NH₃ is preferably in the range of from 0.0001 to0.001. Thus, the value of resistance can be in a desired range.

FIG. 2 shows the relationship between the flow rates O₂/NH₃ and thespecific resistance values of the TiON film. In this case, the flow rateof TiCl gas was 0.02 L/min, the flow rate of NH₃ gas was 0.5 L/min, theflow rate of N₂ was 0.15 L/min, and the flow rate of O₂ was changed inthe range of from 5×10⁻⁵ to 4×10⁻³ L/min (the flow ratio O₂/NH₃ was inthe range of from 0.00001 to 0.008). In addition, during the deposition,the substrate temperature was 550° C., the pressure in the processvessel was 300 mTorr, and the thickness of the film was 50 nm. As shownin FIG. 2, when the flow ratio O₂/NH₃ is in the above described range,the specific resistance (resistivity) value of the TiON film is in therange of from 360 to 7500 μΩ·cm which is an allowable range.

Furthermore, even if another gas, such as NO or N₂O, is used as theO-containing gas, the value of resistance can be in a suitable range byconverting it into the above described range of O₂.

In addition, the barrier characteristic is good if the specificresistance value is about 700 μΩ·cm or higher. Therefore, it can be seenfrom FIG. 2 that the flow ratio O₂/NH₃ is 0.0006 or higher in order toobtain a good barrier characteristic.

Next, the process for forming a TiN-series film (TiNP film), whichcontains Ti, N and P, will be described below.

When NH₃ gas, TiCl₄ gas and PH₃ gas are used as process gases, aTiN-series film (TiNP film), which contains Ti, N and P and which has alow value of resistance while maintaining a relatively good barriercharacteristic, is formed. By using PH₃ gas, it is possible to removethe remaining chlorine by the reducing function of PH₃ gas, so that itis possible to reduce the value of resistance of the TiN-series film. Inthis case, the flow rate of PH₃ is preferably in the range of from 0.04to 0.5 L/min. If it is less than 0.04 L/min, it does not have so greateffect. In addition, if the flow rate of PH₃ is 0.1 L/min or higher, theformed thin film is amorphous and compact, so that the resistance can bedecreased and the barrier characteristic can be good.

FIG. 3 shows the relationship between the flow rates of PH₃ and thespecific resistance values of the TiN-series film. In this case, theflow rate of TiCl₄ gas was 0.02 L/min, the flow rate of NH₃ gas was 0.5L/min, the flow rate of N₂ was 0.15 L/min, and the flow rate of PH₃ waschanged in the range of from 0 to 0.2 L/min. In addition, during thedeposition, the substrate temperature was 430° C. and 550° C., thepressure in the process vessel was 40 Pa, and the thickness of the filmwas 50 nm. As shown in FIG. 3, when the flow rate of PH₃ is 0.04 L/min,the value of resistance clearly decreases. In addition, when thedeposition temperature 550° C., the value of resistance tends to belower. In the case of the deposition at 550° C., when the flow rate ofPH₃ is 0.2 L/min, it is possible to obtain 70 μΩ·cm which is a very lowvalue.

In this case, the relationship between deposition temperatures and thespecific resistance values of the TiN-series film is shown in FIG. 4. Asshown in FIG. 4, when PH₃ is added, the dependence of the specificresistance value on temperature is smaller than when PH₃ is not added,so that the value of resistance is stably low. Furthermore, in FIG. 4,the flow rate of TiCl₄ gas was 0.02 L/min, the flow rate of NH₃ gas was0.5 L/min, the flow rate of N₂ was 0.15 L/min, and the flow rate of PH₃was 0.2 L/min. In addition, the pressure in the process vessel was 40Pa, and the thickness of the film was 50 nm.

Next, the process for forming a TiN-series film (TiONP film), whichcontains Ti, N, O and P, will be described below.

When NH₃ gas, TiCl₄ gas, O₂ gas and PH₃ gas are used as process gassesin the deposition, it is possible to obtain a TiN-series film (TiONPfilm) which contains Ti, N, O and P and which has both of a high barriercharacteristic and a low resistance characteristic. That is, althoughthe barrier characteristic is improved by supplying O₂ gas during thedeposition, the value of resistance increases as the amount of O₂ (theflow ratio O₂/NH₃) increases, as shown in FIG. 5. However, byintroducing P by supplying PH₃ gas, the value of resistance can be lowerthan that when P is not introduced, so that it is possible to obtain aTiN-series film which has both of a high barrier characteristic and alow resistance characteristic. Furthermore, in FIG. 5, the flow rate ofTiCl₄ gas was 0.02 L/min, the flow rate of NH₃ gas was 0.5 L/min, theflow rate of N₂ was 0.15 L/min, the flow rate of PH₃ was 0.2 L/min and 0L/min, and the flow rate of O₂ was changed in the range of from 5×10⁻⁵to 1×10⁻³ L/min (the flow ratio O₂/NH₃ was in the range of from 0.0001to 0.001). In addition, the pressure in the process vessel was 40 Pa,and the thickness of the film was 50 nm.

During the above described deposition, a single TiN-series film wasformed without changing gas. On other hand, if a stacked film comprisinga plurality of TiN-series films is formed as follows, it is possible toobtain a higher barrier characteristic by a smaller thickness.Specifically, as shown in FIG. 6(a), TiCl₄ gas, NH₃ gas and O₂ gas arefirst introduced into the process vessel 11 to form a first thin film 51containing Ti, O and N on an underlying layer 50. Thereafter, the O₂line 44 is closed and the PH₃ gas line is open to introduce TiCl₄ gas,NH₃ gas and PH₃ gas into the process vessel 11 to form a second thinfilm 52 containing Ti, N and P on the first thin film 51.

By forming such a double layer structure, it is possible to improve thebarrier characteristic while maintaining the same specific resistance asconventional specific resistance values if the thickness of the film issmaller than those of conventional films. In this case, the thickness ofthe first thin film 51 is preferably in the range of from 1 to 10 nm,and the thickness of the second thin film 52 is preferably in the rangeof from 3 to 50 nm.

In particular, when a film is used as a barrier layer for a Cu wiringlayer, the thickness of a conventional TiN film must be 50 nm or more inorder to obtain good barrier effects. However, if such a stackedstructure is formed, even if the thickness of the first thin film 51,which is a high barrier TiON film, is in the range of from 1 to 5 nm andthe thickness of the second thin film 52, which is a low resistanceTiN-series film containing P, is in the range of from 5 to 20 nm so thatthe total thickness is decreased to 25 nm or less which is smaller thanthe conventional thickness, the barrier layer can have the same barriercharacteristic and resistance values as those of conventional TiN films.Furthermore, the first thin film and the second thin film may bedeposited in reverse order.

In addition, as shown in FIG. 6(b), a TiN film may have a triple layerstructure. In this case, TiCl₄ gas, NH₃ gas and O₂ gas are firstintroduced into the process vessel 11 to form a first thin film 51containing Ti, O and N on an underlying layer 50. Thereafter, the O₂line 44 is closed and the PH₃ gas line is open to introduce TiCl₄ gas,NH₃ gas and PH₃ gas into the process vessel 11 to form a second thinfilm 52 containing. Ti, N and P on the first thin film 51. Thereafter,the PH₃ gas line 42 is closed and the O₂ line 44 is open again tointroduce TiCl₄ gas, NH₃ gas and O₂ gas into the process vessel 11 toform a third film containing Ti, O and N on the second thin film 52.

By forming such a triple layer structure, it is possible to improve thebarrier characteristic against the films on both sides while maintainingthe same specific resistance and the thickness of the film is smallerthan those of conventional films. In this case, the thickness of thefirst thin film 51 and third thin film 53 is preferably in the range offrom 1 to 10 nm, and the thickness of the second thin film 52 ispreferably in the range of from 3 to 50 nm. Such a triple layerstructure can be effectively used as, e.g., a top electrode of acapacitor portion having an insulating layer of Ta₂O₅ or RuO.

The above described double layer and triple layer structures can beformed in a short time without any difficulty since each layer can becontinuously formed only by switching gases in the same system.

Furthermore, in either case of the above described double layer andtriple layer structures, a P containing gas may be introduced into theprocess vessel when the first thin film 51 and/or the third thin film 53is formed. When a thin film containing Ti, O, N and P is formed or whenthe second thin film 52 is formed, if an O-containing gas is introducedinto the process vessel, a thin film containing Ti, O, N and P can beformed. Thus, it is possible to further improve characteristics inaccordance with a film to be obtained.

As described above, the TiN-series thin film obtained according to thepresent invention has at least one of a high barrier characteristic anda low resistance characteristic to be suitable for a barrier layer for ametal wiring layer and for a top electrode of a capacitor even if it hasa single layer structure or a stacked structure.

The TiN-series thin film according to the present invention is actuallyused as a film structure which is stacked on another layer.Specifically, as shown in, e.g., FIG. 7, a TiN thin film 55 of any oneof a thin film containing Ti, O, and N, a thin film containing Ti, N andP, and a thin film containing Ti, O, N and P is provided between theother first layer 54 and the second layer 56.

Such a film structure can be applied to various portions ofsemiconductor devices. For example, a contact layer, such as a Ti thinfilm, a TiSi thin film or a CoSi thin film, is formed as the first layer54, and the TiN thin film 55 according to the present invention isformed thereon. Then, a metal layer, e.g., W, Al or Cu layer, which isapplied as a wiring layer or an embedded wiring portion, is formedthereon as the second layer. In addition, a CoSi thin film serving asthe first layer 54 may be used as a gate electrode, and a metal layerserving as a wiring layer may be formed via a TiN-series thin filmelectrode according to the present invention serving as a barrier layer.Moreover, such a film structure can be applied to a capacitor portion ormetal gate electrode portion of a DRAM as will be described later.

When the TiN-series thin film thus used according to the presentinvention is formed by the CVD, before the TiN-series film is formed bythe above described system shown in FIG. 1 (i.e., before NH₃ gas, TiCl₄gas, and O₂ gas and/or PH₃ gas are introduced), or after the supply ofNH₃ gas and PH₃ gas is stopped to complete the formation of the thinfilm, or at both times, an O-containing gas (02 gas in the abovedescribed system shown in FIG. 1) is introduced into the process vessel11. Specifically, a first layer of, e.g., a Ti thin film, a TiSi thinfilm and a CoSi thin film, is first formed by the PVD or CVD (the plasmaCVD or thermal CVD). Thereafter, before the TiN-series thin film isformed by the CVD, O₂ gas is introduced into a CVD process vessel, andafter the TiN-series thin film is formed, O₂ gas is introduced again.Thereafter, a second layer of a metal of, e.g., Al, W or Cu, is formedby the PVD or CVD (the plasma CVD or thermal CVD). Furthermore, any oneof the introductions of O₂ gas may be omitted.

By the introduction of oxygen at this time, a thin oxide film is formedon the underlying first layer and/or the TiN-series thin film, so thatit is possible to enhance the barrier characteristic against theadjacent first layer and/or second layer. Therefore, when the thin filmcontaining Ti, O and N and the thin film containing Ti, O, N and P areformed, it is possible to reduce the amount of O to maintain a goodbarrier characteristic. Furthermore, even if the TiN-series thin film isthe above described stacked film, such effects can be obtained byintroducing an O-containing gas before and/or after the thin films arecontinuously deposited in the process vessel 11.

Referring to FIGS. 8(a) through 8(c), examples of a TiN-series thin filmaccording to the present invention, which is used as a contact part of ametal wiring layer, will be described below.

In the example shown in FIG. 8(a), an interlayer dielectric film 61 isformed on a silicon substrate 60, and a contact hole 62 extendingdownwardly to an impurity diffusion region 60 a of the silicon substrate60 is formed in the interlayer dielectric layer 61. On the surface ofthe interlayer dielectric film 61 and contact hole 62, an Ti thin film63 and a TiN-series thin film 64 according to the present invention areformed. On the TiN-series thin film 64, a metal wiring layer 66 of,e.g., Cu or W, is formed. This metal wiring layer 66 is also filled inthe contact hole 62, so that the conducting state between the impuritydiffusion region 60 a of the silicon substrate 60 and the metal wiringlayer 66 is established.

Since the TiN-series thin film 64 has a higher barrier characteristicthan those of conventional TiN thin film, the presence of the TiN-seriesthin film 64 can very effectively prevent the formation of a compound bya reaction of Cu or W with Si. In addition, since the TiN-series thinfilm 64 has such a high barrier characteristic, it is possible to veryeffectively prevent the diffusion of Cl₂. The TiN-series thin film 64 ispreferably a TiON film or a TiONP film in order to obtain a high barriercharacteristic. In addition, a TiNP film may be used since it has arelatively high barrier characteristic if it is amorphous. In this case,it is not always required to provide the Ti thin film 63.

In the example shown in FIG. 8(b), similar to the example shown in FIG.8(a), an interlayer dielectric film 61 is formed on a silicon substrate60, and a contact hole 62 extending downwardly to an impurity diffusionregion 60 a of the silicon substrate 60 is formed in the interlayerdielectric layer 61. On the surface of the interlayer dielectric film 61and contact hole 62, an Ti containing film 69 having a double stackedstructure of a TiNP film 67 and a TiON film 68 is provided. On theTiN-series thin film 69, a metal wiring layer 66 of, e.g., Cu or W, isformed. This metal wiring layer 66 is also filled in the contact hole62, so that the conducting state between the impurity diffusion region60 a of the silicon substrate 60 and the metal wiring layer 66 isestablished. Thus, the TiNP film 67 functions as a contact layer, andthe TiON film 68 functions as a barrier layer, so that it is possible toobtain better characteristics than those of conventional Ti/TiN films.

In the example shown in FIG. 8(c), similar to the example shown in FIG.8(a), an interlayer dielectric film 61 is formed on a silicon substrate60, and a contact hole 62 extending downwardly to an impurity diffusionregion 60 a of the silicon substrate 60 is formed in the interlayerdielectric layer 61. In the contact hole 62, an embedded wiring layer(plug) 70 of a TiNP thin film is formed, and a metal wiring layer 72 ofCu or W is formed thereon via a TiON barrier layer 71. As describedabove, the TiNP thin film has a low resistance, it can be thus used asthe embedded wiring layer.

Furthermore, the metal wiring layers 66 and 72 may be made of any one ofmetals other than Cu and W, or an alloy. In addition, the metal wiringlayers 66 and 72 may be applied to via hole portions conducting to otherconductive layers, in addition to the contact hole portion.

Referring to FIGS. 9(a) through 9(c), examples of a TiN-series thin filmaccording to the present invention, which is applied to a capacitorstructure of a DRAM or the like, will be described below.

In the example shown in FIG. 9(a), a bottom electrode layer 81 ofamorphous silicon is connected to an impurity diffusion region 80 a of asilicon substrate 80. On the bottom electrode layer 81, an insulatinglayer 83 of Ta₂O₅ or RuO is formed via an SiN barrier layer 82 which isformed by the rapid thermal nitrization (RTN) process of silicon. On theinsulating layer 83, a top electrode layer 84 of a TiN-series thin filmaccording to the present invention is formed. On the top electrode layer84, a metal wiring layer (not shown) is formed.

Conventionally, a TiN film is used as the top electrode layer 84.However, there is a problem in that the heat treatment in a post-processcauses O of Ta₂O₅ to diffuse into the TiN film to change to TiO, so thatthe thickness of the TiN film decreases to increase the thickness ofTa₂% to reduce the capacity. Such a problem can be solved by using thetop electrode 84 of the TiN-series thin film according to the presentinvention. In this case, the TiN-series film constituting the topelectrode 84 is preferably a TiON film or a TiONP film in order to holda high barrier characteristic. In addition, if the stacked structure ofthe TiN-series film and a TiNP film is provided, it is possible toobtain a good barrier characteristic while maintaining a usual specificresistance even if the thickness of the stacked structure is small.Moreover, the triple stacked structure of TiON film or TiONP film/TiNPfilm/TiON film or TiONP film is provided, it is possible to effectivelyprevent the diffusion of oxygen and metals on both sides of the topelectrode layer 84.

The basic structure of the example shown in FIG. 9(b) is the same asthat of the example shown in FIG. 9(a). However, in the example shown inFIG. 9(b), a barrier layer 85 of a TiN-series thin film according to thepresent invention is formed in place of the SiN barrier layer 82 on thebottom electrode layer 81. The TiN-series thin film constituting thebarrier layer 85 is preferably a TiON film or a TiONP film in order tohold a high barrier characteristic. In addition, the stacked structureof the TiN-series thin film and a TiNP film may be also used.

While the TiN-series thin film according to the present invention hasbeen applied to the metal isolation silicon (MIS) structure, theTiN-series thin film according to the present invention may be appliedto a metal isolation metal (MIM) structure which uses a metal, such asruthenium, in place of amorphous silicon for a bottom electrode. Inaddition, a TiN-series thin film according to the present invention maybe used as a bottom electrode having the MIM structure. This example isshown in FIG. 9(c). In this example, a bottom electrode 86 of a TiNPfilm is provided in place of the bottom electrode 81 of amorphoussilicon. On the bottom electrode 86, a barrier layer 87 of a TiON filmor a TiONP film is provided. Furthermore, an insulating layer 83 and atop electrode layer 84 have the same structures as those in the examplesshown in FIGS. 9(a) and 9(b).

In the examples shown in FIGS. 8(a) through 8(c) and 9(a) through 9(c),the TiN-series thin film according to the present invention, and themetal wiring or the insulating layer of Ta₂O₅, RuO or HfO₂ can becontinuously deposited using a cluster tool type process system shown inFIG. 10. This system comprises: a transfer chamber 90 which is arrangedat the center; and two cassette vessels 91 and 92, a degassing vessel93, a deposition unit 94, a pre-cleaning unit 95, a deposition unit 96,a deposition unit 97 and a cooling vessel 98, which are arranged aroundthe transfer chamber 90. In addition, a semiconductor wafer W isintroduced into and carried out from each of the vessels by means of atransfer arm 99 which is provided in the transfer chamber 90.

In such a deposition system, one of the deposition units 94, 96 and 97is provided for forming a TiN-series thin film according to the presentinvention, and other units are provided for forming a metal wiring or aninsulating layer of Ta₂O₅ or RuO. As an example of the operation of adeposition process, the formation of the capacitor structure shown inFIG. 9(b) will be described below.

First, a semiconductor wafer W is taken out of the cassette vessel 91 bymeans of the transfer arm 99, and introduced into the pre-cleaning unit95 utilizing the inductively coupled plasma (ICP) or remote plasma. Inthe pre-cleaning unit 95, oxides and so forth on the surface of thewafer W are removed by using at least one of Ar, H₂ and BrCl₃. Then, thesemiconductor wafer W is introduced into the degassing vessel 93 bymeans of the ram 99 to degas the wafer. Thereafter, a barrier layer of aTiN-series thin film according to the present invention is deposited onthe semiconductor wafer W by means of any one of the deposition units94, 96 and 97. Thereafter, the wafer W is introduced into anotherdeposition unit by means of the arm 99 while maintaining the vacuumstate, to form an insulating layer of Ta₂O₅. Thereafter, the wafer W isintroduced into the first deposition unit again to deposit a topelectrode layer of a TiN-series thin film according to the presentinvention. According to circumstances, the wafer W is introduced intoanother deposition unit to form a metal wiring layer on the topelectrode layer. Thus, a predetermined deposition process is completed,and then, the semiconductor wafer W is cooled by means of the coolingvessel 98 to be housed in the cassette vessel 92.

Referring to FIGS. 11(a), 11(b) and 12, examples of a TiN-series thinfilm according to the present invention, which is applied to a gateelectrode, will be described below.

In the example of FIG. 11(a), a gate electrode 104A is provided on asilicon substrate 100 via an insulating film 101. The gate electrode104A comprises a gate oxide film 115, a TiNP thin film 103 and apolysilicon film 102 between those films 115 and 103. On the TiNP thinfilm 103, a W wiring layer 106 is formed. That is, WSi of the gateelectrode of the conventional double layer structure of a polysiliconand tungsten silicide (WSi) is replaced with TiNP. Furthermore,reference number 105 denotes a spacer of SiN. Since TiNP used for thegate electrode has a low resistance and an excellent barriercharacteristic and is thermally stable, the structure of FIG. 11(a) hassuperior characteristics to those of the gate electrode of theconventional double structure of a polysilicon and WSi. Moreover, if itis amorphous, the barrier characteristic can be further enhanced, sothat it is possible to obtain more excellent characteristics.Specifically, it is possible to achieve a higher speed, and it ispossible to reduce the thickness of the film. The thickness of each ofthe polysilicon and tungsten silicide (WSi) of the gate electrode of theconventional double layer structure of the polysilicon and tungstensilicide is 100 nm, so that the total thickness is 200 nm. On the otherhand, the thickness of the TiNP layer on the polysilicon may be in therange of from 10 to 50 nm, so that the total thickness may be in therange of from 110 to 150 nm which is far thinner than that of the gateelectrode of the conventional double layer structure. When TiNP isamorphous to improve the barrier characteristic, the thickness can beparticularly small.

In the example of FIG. 11(b), a gate electrode 104B comprising a gateoxide film 115 and a TiNP thin film 107 directly formed on the film 115is provided in place of the gate electrode 104 of FIG. 11(a). Asdescribed above, the TiNP thin film has a low resistance, a high heatresistance and an excellent barrier characteristic. Therefore, the TiNPthin film alone can also obtain excellent characteristics as a gateelectrode similar to the double layer structure of polysilicon/TiNP. Inthis case, the thickness of the TiNP gate electrode 107 is sufficient tobe in the range of from about 20 nm to about 50 nm, so that it ispossible to realize a very thin gate electrode. Thus, also in the caseof the TiNP layer alone, it is possible to particularly reduce thethickness by causing the TiNP layer to be amorphous to improve thebarrier characteristic. Incidentally, a TiON thin film may be formedbetween the gate oxide film 115 and the TiNP thin film 107.

In the example of FIG. 12(a), a gate electrode 104C is used in place ofthe gate electrodes 104A and 104B of FIG. 11. The gate electrode 104Ccomprises a gate oxide film 115, a polysilicon film 116, a CoSi thinfilm 108 and a barrier layer 109. The barrier layer 109 is a TiN-seriesthin film formed by the CVD according to the present invention. The CoSithin film 108 is formed for obtaining a contact resistance. The CoSithin film 108 and the polysilicon film 116 have low resistance and canprovide excellent characteristics to the gate electrode 104C, so that itis possible to reduce the thickness of the gate electrode itself. Inaddition, by the barrier layer 109 of the TiN-series thin film accordingto the present invention, it is possible to obtain an excellent barriercharacteristic.

In the example of FIG. 12(b), an insulating layer 110 of high dielectricmaterial is formed on a silicon substrate 100. The insulating layer 110is made of at least one of SiO₂, HfO₂, Ta₂O₅, RuO, BST, PZT (Pb(Zr,Ti)O₃: lead zirconate titanate). Then, a barrier layer 111 of aCVD-TiN-series thin film according to the present invention is formedthereon, and a metal gate electrode 112 of Al, W or Cu is formedthereon. In FIG. 12(b), reference numbers 113 and 114 denote a sourceand a drain, respectively. Thus, a metal gate structure 118 capable ofresponding to accelerating is constructed. The barrier layer 11 of theCVD-TiN-series thin film according to the present invention caneffectively prevent the relative diffusion between the gate electrode112 and an insulating layer 110 of a high dielectric material.

An example of a TiN-series thin film according to the present invention,which is applied to a contact structure for forming a wiring in adiffusion region formed in the major surface of a semiconductorsubstrate, will be described below. In an example of FIG. 13, a contactlayer 122 of a TiSi thin film or a CoSi thin film is formed on adiffusion region (source or drain) 121 which is formed in the majorsurface of a silicon substrate 120. Then, a barrier layer 123 of aTiN-series thin film according to the present invention is formedthereon, and a wiring layer 124 of Al, W or Cu is formed thereon. Inthis case, since the TiSi thin film and the CoSi thin film have a lowresistance, these thin films can have good characteristics as a contactlayer, and it is possible to obtain a good barrier characteristic by theTiN-series thin film according to the present invention, so that it ispossible to obtain a contact structure having very good characteristics.Furthermore, reference number 125 denotes a gate electrode.

Furthermore, the present invention should not be limited to the abovedescribed preferred embodiments, but the invention can be modified invarious ways. For example, the conditions in each process are merelydescribed as an example, so that the conditions may be suitably set inaccordance with processes. In addition, the substrate to be used shouldnot be limited to the semiconductor wafer, but it may be anothersubstrate. Moreover, another layer may be formed on the surface of thesubstrate. In addition, while the TiN-series thin film has beendeposited by the thermal CVD in the above described preferredembodiments, the present invention should not be limited thereto, butother CVDs may be used. However, if the thermal CVD is used for thedeposition, the TiN-series thin film can be relatively easily formedwithout the need of any complicated processes, so that the thermal CVDis preferably used for the deposition.

Although the preferred embodiments have been represented by theTiN-series thin films, the present invention is not limited to thedeposition of the TiN-series thin films. That is to say, the presentinvention can be applied to metallic nitride series thin films otherthan the TiN-series thin films. Such metallic nitride series thin filmsinclude Al, W, Zr, Hf, Ru, Ta, and La nitride series thin films. Todeposit each metallic nitride series thin film, corresponding metallicelement containing gas and N-containing gas are used as the processgases. O-containing gas can be used as an additional process gas.

For example, Al-containing gas is at least one of Al (OC₂H₅)₃ gas,Al(OCH₃)₃ gas and AlCl₃ gas. W-containing gas is at least one of WF₆ gasand W(CO)₆ gas. Zr-containing gas is at least one of ZrCl₄ gas andZr[N(OC₂H₅)₂]₄ gas. Hf-containing gas is at least one of HfCl₄ gas andHf[N(OC₂H₅)₂]₄ gas. Ru-containing gas is at least one of Ru(CO)₅ gas andRuCl₃ gas. Ta-containing gas is at least one of TaCl₅ gas, Ta(OC₂H₅)₃gas and Ta(OCH₃)₃ gas. La-containing gas is at least one of LaCl₃ gas,La(OC₂H₅)₃ gas and La(OCH₃)₃ gas. The N-containing gas is NH₃ gas andthe O-containing gas is at least one of O₂ gas, NO gas and N₂O gas.

When depositing the TiN-series thin films, as Ti-containing gases, TiI₄gas, Ti(OC₂H₅)₃ gas and/or Ti(OCH₃)₃ gas can be used in addition to/inplace of the TiCl₄ gas. Furthermore, TiN-series thin films can contain B(boron) in place of P (phosphorus). In this case, at least one of BH₃gas and B₂H₆ gas is used in place of PH₃ gas.

The metallic nitride series thin film can be generally used as anintermediate layer between first and second conductive layers and/or anintermediate layer between a dielectric layer on the first conductivelayer and the second conductive layer. In this case, the firstconductive layer may be one of a TiSi layer, a CoSi layer and a Silayer, and the second conductive layer may be one of an Al layer, a Wlayer and a Cu layer. In addition, a polysilicon layer can be used asthe first conductive layer. The dielectric layer may comprise at leastone of SiO₂, SiON, HfO₂, ZrO, Ta₂O₅, RuO, PZT and BST.

While the present invention has been disclosed in terms of the preferredembodiment in order to facilitate better understanding thereof, itshould be appreciated that the invention can be embodied in various wayswithout departing from the principle of the invention. Therefore, theinvention should be understood to include all possible embodiments andmodification to the shown embodiments which can be embodied withoutdeparting from the principle of the invention as set forth in theappended claims.

1-38. (canceled)
 39. A gas processing apparatus for processing an objectwith a gas, said apparatus comprising: a process vessel for containingtherein said object; an exhaust system for exhausting an atmosphere insaid process vessel; a gas supply source for supplying said gas; a gasflow line connected between said process vessel and said gas supplysource; a mass flow controller provided in said gas flow line; a firston-off valve provided in said gas flow line between said gas supplysource and said mass flow controller; a second on-off valve provided insaid gas flow line between said mass flow controller and said processvessel; and a pre-flow line connected to said gas flow line between saidmass flow controller and said second on-off valve, for exhausting saidgas without introducing same into said process vessel; and a thirdon-off valve provided in said pre-flow line.
 40. The apparatus as setforth in claim 39, wherein a shower head is provided in a top of saidprocess vessel for discharging said gas supplied through said gas flowline into said process vessel.
 41. The apparatus as set forth in claim39, wherein said exhaust system includes an exhaust line connected to abottom of said process vessel.
 42. The apparatus as set forth in claim41, wherein a downstream-end of said pre-flow line is connected to saidexhaust line.
 43. The apparatus as set forth in claim 39, wherein saidobject is a substrate and said gas is a material gas for depositing athin film on said substrate.
 44. A cluster tool type process systemcomprising: a cassette vessel for housing a plurality of objects; aplurality of gas processing units for processing an object with a gas;and a transfer vessel connected to said cassette vessel and said gasprocessing units, said transfer vessel being provided with a transferarm therein, at least one of said gas processing units comprising: aprocess vessel for containing therein said object; an exhaust system forexhausting an atmosphere in said process vessel; a gas supply source forsupplying said gas; a gas flow line connected between said processvessel and said gas supply source; a mass flow controller provided insaid gas flow line; a first on-off valve provided in said gas flow linebetween said gas supply source and said mass flow controller; a secondon-off valve provided in said gas flow line between said mass flowcontroller and said process vessel; a pre-flow line connected to saidgas flow line between said mass flow controller and said second on-offvalve, for exhausting said gas without introducing same into saidprocess vessel; and a third on-off valve provided in said pre-flow line.45. The system as set forth in claim 44, wherein said at least one ofsaid gas processing units is a deposition unit for depositing a thinfilm on a substrate as said object with a material gas.
 46. The systemas set forth in claim 45, further comprising a pre-cleaning unitconnected to said transfer vessel.
 47. The system as set forth in claim46, wherein said pre-cleaning unit is arranged for a pre-cleaning ofsaid substrate utilizing an inductively coupled plasma or a remoteplasma.
 48. The system as set forth in claim 45, further comprising adegassing vessel connected to said transfer vessel.
 49. The system asset forth in claim 45, further comprising a cooling vessel connected tosaid transfer vessel.
 50. A method for processing an object with a gas,said method comprising the steps of: arranging said object in a processvessel; evacuating said process vessel; and introducing said gas intosaid process vessel through a gas flow line provided with a mass flowcontroller to process said object with said gas, said method furthercomprising, between said evacuating step and said introducing step, thestep of pre-flowing said gas through a pre-flow line connected to saidgas flow line between said mass flow controller and said process vesselto exhaust said gas, without introducing said gas into said processvessel.
 51. The method as set forth in claim 50, wherein said object isa substrate and said gas is a material gas for depositing a thin film onsaid substrate.